There is a recognized need for a mobile, self-contained pump system to be used in various applications. The military uses portable pumps to pump water (and/or fuel) from a source to a remote location where military personnel are located. In some military applications, a series of pump units spaced miles apart are used to transfer water from a source of fresh water such as a lake to a location hundreds of miles inland. Civilian applications of portable pump units include emergency pumping of flood waters from a flooded location and the temporary pumping or transfer of sewage between transfer stations when the stationary pump units are inoperative. Portable engine driven air compressors are also used in many applications. Both engine driven liquid pumps and engine driven air compressors share a common problem - both are usually extremely noisy in operation. The noise generated by these portable units is often found to be highly objectionable in residential areas. In addition, the pump operators find working around, and operating these units, to be very uncomfortable and fatiguing due to the high noise level.
In the past, efforts have been made to quiet portable, engine driven air compressors. Completely shrouding or enclosing the machinery is not possible since many of the components, i.e. engine, require cooling air to remove waste heat. In the case of engine driven compressors, muffling the exhaust of the engine does not usually provide sufficient quieting since the engine driven compressor is also a substantial source of noise. In addition, the engine itself radiates noise from its surfaces.